The ground was officially broken yesterday for the six billion electron volt Cambridge Electron Accelerator, with President Pusey and Chancellor Julius A. Stratton of M. I. T. wielding the double-handled spade together.

This unique tool was designed to symbolize the cooperation between the two universities in building and operating the $6.5 million machine, which is being financed by the Atomic Energy Commission. After gingerly poking at the earth, the two hoisted a shovelful over their shoulders. Most of the dirt fell on themselves.

The spot at which the ground was broken marked the probable center of a circular tunnel 236 feet in diameter which will house the major part of the accelerator, to be the largest of its type in the world on its completion early in 1960.

Other work has been going on for some time at the site which is just off Oxford St., north of the University Museums and next to the Harvard Cyclotron. The skeletal structure of one of the major adjacent buildings is nearing completion.

The machine is designed to accelerate electrons, fundamental atomic particles, to close to the speed of light and at energies never before attained. These particles will then be studied by allowing them to hit various targets and other instruments.

Energy is imparted to the travelling particle in a series of electrical "kicks," each increasing its speed until a total of six billion electron volts is accumulated.

Work to be Unclassified

None of the work will be classified, and it will all be in the field of so-called "fundamental research." Scientists from Harvard, M.I.T., and other New England colleges and universities will all be able to work on the machine.

Yesterday afternoon's ceremony was led by M. Stanley Livingston, professor of Physics at M.I.T. and director of the project. After presenting the members of the executive committee to the audience, he introduced President Pusey and Chancellor Stratton. Each of them spoke briefly on the role of the accelerator in research, and on the cooperation between the two universities which has made Cambridge one of the most important research centers in the scientific world.

Eugene Booth, professor of Physics at Columbia University, represented the Atomic Energy Commission with a few brief remarks to close the ceremony. James R. Killian, Jr., president of M.I.T., who was scheduled to speak and assist President Pusey in the ground-breaking, was unable to attend.